1. Field of Invention
The present invention relates to an earphone, and more particularly to an earphone without impulse noise surroundings blockade, wherein the sound outside can be caught by the human ear so that any events outside are able to be realized at once without taking off the earphone. Moreover, the present invention can also prevent conductive hearing loss caused by the direct impact of the impulse noise.
2. Description of Related Arts
An ordinary earphone, referring FIGS. 1 to 3B of the drawings, comprises a earphone housing 10, a loudspeaker 20, and a sound outlet cover 30, wherein the earphone housing 10 comprising a sound chamber 11 and an open-end 12. The loudspeaker 20 is mounted on the sound chamber 11 of the earphone housing 10. The sound outlet cover 30 is affixed on the open-end 12 of the earphone housing 10, wherein a plurality of sound outlet meshes 31 is formed on the surface of the sound outlet cover 30. The impulse noise output end 21 of the loudspeaker 20 is faced to the sound outlet meshes 31 of the sound outlet cover 30. When the earphone is hanged between a tragus A1 and an antitragus A2 of the human ear A (as shown in FIG. 1), sound emitted from the impulse noise output end 21 of the loudspeaker 20 transmits through the sound outlet meshes into the ear canal A3 of the human ear A. As shown in FIG. 3B, it is apparent that the sound wave impacts directly on the eardrum and the ear canal A3 is totally obstructed by the earphone.
Form the above, it is realized that when people are using the ordinary earphone 10, the sound emitted by the loudspeaker 20 will all transmit through the meshes 31 of the sound outlet cover 30 to the human ear A. The sound from outside cannot pass through the earphone housing 10 and cannot combine the sound emitted by the loudspeaker 20 together and then transmit to the human ear A. So, when people wear the ordinary earphone 10, they can only hear the sound from the loudspeaker 20 and will completely be blocked hearing and knowing from outside because, as shown in FIG. 3B, the speaker 20 itself blocks the ear canal A3 that may danger their lives especially while they are driving or walking on the street.
Furthermore, in 1997, UT Southwestern Medical Center stated: xe2x80x9capproximate 20% of American Teenagers, between 13-19 have hearing disability. The major cause of the hearing loss is that people exposed to the noise especially the impulse noise from the earphone.xe2x80x9d People should concern the control of the sound volume while using the traditional earphone (continuous hearing not more than one hour or six hours per day when sound pressure at 105 dB or 95 dB respectively). In fact, this flash impulse noise contains high sound pressure and may damage the eardrum or middle ear hearing loss. It is called Conductive Hearing Loss. America""s medical report recently stated that the percentage of people having the Conductive Hearing Loss is gradually increasing since the earplug type earphones are improperly used listen to the hot music such as Rock and Roll.
In other words, sound emitted by an ordinary earphone contains impulse noise. When an ordinary earplug type earphone is used, the impulse noise will directly impact to the external auditory canal A3 of the human ear A and make people feel uncomfortable. The continuous use of an ordinary earplug type earphone will result in damage of the middle ear and the cause of hearing loss to the people.
U.S. Pat. No. 4,736,435, Yokoyama et al suggests a plurality of through-openings which are required to be provided on the back portion of the outer casing, which may be small as possible and can not be enlarged larger than a predetermined size because they are used to avoid the sound characteristic be deteriorated. However, the loudspeaker thereof is installed in the front end of the housing that itself blocks the ear canal so that even sound from outside may enter the earphone through the through openings on the back portion thereof but the sound from outside is also blocked by the loudspeaker and the user has no way to listen anything from outside, as shown in FIG. 6 of the drawings.
U.S. Pat. No. 5,949,896, Nageno, merely discloses an earcup type headphone that contains through holes to enable sound from outside to enter the box body. However, earcup type headphone is absolutely different to earplug type earphone because that the earplug type earphone has a relative small size and is adapted to be inserted into the entrance of the ear canal.
Moreover, both the ""435 and ""896 patents are constructed to directly inlet the high impulse noise emitted from the loudspeaker into the ear canal A3 of the human ear A, as indicated in FIGS. 1 to 3 that may cause the impulse noise directly impacting to the external auditory canal A3 of the human ear A and make people feel uncomfortable. Like all the conventional earphone or headphone, the continuous use of the ""435 and ""896 patents may result in damage of the middle ear and the cause of hearing loss to the people. Practically, such problems are remained unsolved in both the ""435 and ""896 patents.
In addition, in the past 20 years, so much progress has been achieved in designing and arranging the audio speaker system, such as xe2x80x9cDolby Surround Soundxe2x80x9d, xe2x80x9cDts 5.1xe2x80x9d channel and home theater. But there are very few changes have been made in the acoustic field of the earplug type earphone.
In conclusion, there are numerous of disadvantages of the ordinary earphone that need to be solved as follows:
1. Cause hearing discomfort and eardrum injury if use them intensively.
No matter how advanced techniques have become in the past 20 years, the basic structure of earphones always has a speaker directly against the ear canal and eardrum.
The powerful sound wave keeps pounding on the delicate and fragile eardrum within the short and limited chamber of the ear canalxe2x80x94it is just like a fried cracker exploding in a tightly grasped hand! They symptom of itch or pain in the ear canal will be detected after lengthy use, which is an indication of eardrum injury.
2. Threaten safety when use them as a portable hands-free while driving or having outdoor activities.
Safety is the most imperative concern in communication, this is why we need hands-free to eliminate the risk of radiation jeopardy as well as maintain traffic safety while driving. But the traditional hands-free headset has the following insufficiencies:
i) It blocks the wearing ear. From the medical point of view, only when both ears hear sound simultaneously can a person identify the direction of it. Otherwise they cannot tell which direction it comes from. That is very dangerous while driving or having outdoor activities.
ii) It causes the imbalance of both ears thereby dizziness after long tie usage. That is dangerous as well.
iii) Because of the discomfort of most of the earphones (either too large or awkward in shape), people usually take them on and of frequently and only wearing them when they get phone calls. This will cause a fatal risk while driving.
3. Cause inconvenience when use them for stereo listening while working or talking to your friends.
Do you ever ask, xe2x80x9cWhy can""t I privately listen to fabulous music and talk with friends simultaneously? Why can""t I listen favorite songs privately at eh beach, while hearing the singing seagulls and the gentle paddling of sea waves at the seashore?xe2x80x9d Nearly all traditional earphones are designed with such a purpose as to totally isolate the exterior environment.
4. Not feasible for communication because they enforce low and high frequency noise and decrease sound clarity.
The length of an adult""s ear canal is about 2.4 cm. From the physical point of view, when both ends of the canal are obstructed, it is good to reproduce the frequency at around 6000 Hz (the length is about twice of the canal length) and lower than 500 Hz (the canal length is far shorter than this wave length). But it is bad to reproduce the frequency around 3000 Hz (the canal length is quarter of the wave length). Currently, traditional earphone design happens to obstruct both ends of the ear canal, creating just the same phenomena as mentioned above. Nevertheless current communication devices entail good 3000 Hz response (the very point that consonants exist) yet suppress the response under 500 Hz and over 5000 Hz (the site that low and high frequency noises exist). This is the current earphone weakpoint.
5. Fail to produce a spatial effect without the aid of electronic devices.
xe2x80x9cSpace is the mother of musicxe2x80x9d. No matter how good the home theater system we have, if we attach our ear against a high-end speaker (tweeter), what we can hear is just a low-end flat sound. With the traditional earphones there is less chance to gain the originally recorded spatial effect.
6. Restricted in the design of shape and size.
Most traditional earphones are designed such to put the speakers, wearing part inside the ear. So the wearing part sometimes is too big, causing discomfort or too small being easily dropped from the ear. As the size and shape of the wearing part is restricted, thus ignores other groups of users such as women and children.
The main object of the present invention is to provide an earplug type earphone without impulse noise and surroundings blockade, wherein the earphone is constructed to enable sound from outside passing through the earphone housing and combining with the sound emitted by the loudspeaker before transmitting into the ear canal of the human ear. While the present invention is used to listen to the music, people are still able to hear the sound from outside and realize the events outside to keep away from dangerous. The present invention substantially overcomes the disadvantages of the ordinary earplug type earphone which completely blocks hearing from outside.
Another object of the present invention is to provide an earplug type earphone without impulse noise and surroundings blockade, wherein sound emitted by the present invention does not contain any impulse noise. When the earphone is used to listen music, the present invention can prevent not only the impulse noise from directly impact to the middle ear but also the damage of the middle ear and the cause of hearing loss.